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SR_ERC Report_Mei Lin SP_200806_v3_FINAL
ENVIRONMENTAL REVIEW COMMITTEE REPORT
ERC Meeting Date: August 10, 2020
Project File Number: PR20-000102
Project Name: Mei Lin Short Plat
Land Use File Number: LUA20-000060, SHPL-A, ECF, MOD
Project Manager: Alex Morganroth, Senior Planner
Owner: Maggie Wang, Ideal Living LLC, 12005 NE 173rd Ct, Bothell, WA 98011
Applicant: Gil Hulsmann, Abbey Road, Group, 2102 E Main Ave, Suite 109, Puyallup, WA
98372
Contact: Phil Becker, Abbey Road Group, 2102 E Main Ave, Suite 109, Puyallup, WA
98372
Project Location: 1833 NE 12th St
Project Summary: The applicant is requesting Environmental (SEPA) Review, Preliminary Short Plat
approval, and street modification for the subdivision of a 41,000 sq. ft. (0.94 ac)
parcel into three new lots and one critical areas tract. The subject property is
located at 1833 NE 12th St, is zoned Residential-8 (R-8), and is designated
Residential Medium Density in the Comprehensive Plan Land Use Map. The
proposal is to subdivide the currently vacant project site into three (3) lots in
order to construct new single-family home on each lot. The new homes would
take access directly from NE 12th St. The proposed lots are all 5,000 feet in size
and yield a net density of 7.8 du/ac. The project is subject to SEPA review due to
the presence of protected slopes on the site. The property is mapped within a
High Erosion Hazard, High and Moderate Landslide Hazard areas, and protected
slopes on over half of the westerly portion of the site, which continue west to SR
900 and I-405. The applicant is proposing to retain 14 trees outside of the critical
areas and all trees within the critical areas.
Exist. Bldg. Area SF: 0 Proposed New Bldg. Area (footprint):
Proposed New Bldg. Area (gross):
N/A
N/A
Site Area: 0.94 ac Total Building Area GSF: N/A
STAFF
RECOMMENDATION:
Staff Recommends that the Environmental Review Committee issue a
Determination of Non-Significance - Mitigated (DNS-M).
DocuSign Envelope ID: 44E7B13B-E61D-42E2-9010-CB07930C65F3
City of Renton Department of Community & Economic Development
Mei Lin Short Plat
Staff Report to the Environmental Review Committee
LUA20-000060, SHPL-A, ECF, MOD
Report of August 10, 2020 Page 2 of 5
SR_ERC Report_Mei Lin SP_200806_v3_FINAL2
ENVIRONMENTAL REVIEW
In compliance with RCW 43.21C.240, the following environmental (SEPA) review addresses only those project
impacts that are not adequately addressed under existing development standards and environmental regulations.
A. Environmental Threshold Recommendation
Based on analysis of probable impacts from the proposal, staff recommends that the Responsible Officials:
Issue a DNS-M
B. Mitigation Measures
1. The applicant shall comply with the recommendations of the geotechnical report prepared by
Krazen & Associates, prepared on July 9, 2020, or an updated report submitted at a later
date.
2. The applicant shall retain a licensed geotechnical engineer to be present on site during any
earthwork activities related to site preparation on proposed Lot 3. The engineer shall be
responsible for ensuring that the recommendations in the Krazen & Associates report, dated
July 9, 2020 (or an updated report), are followed.
3. The applicant shall erect a 6-foot tall temporary chain-link fence at the edge of the 15-foot
buffer and additional 15-foot structure setback (total of 30 feet) in order to ensure no
disturbance of vegetation or impacts in the geological hazard area identified in the report
prepared by Krazen & Associates. The fencing shall be affixed to the ground using metal
stakes or similar to prevent movement and shall include warning signage regarding the risks
of any disturbing vegetation or earth in the buffer or setback area. The fencing shall be
installed prior to the start of any work on the site and shall remain in place until all structures
on Lot 3 receive a sign-off on the building permit final inspection.
4. The applicant’s geotechnical engineer shall review the project’s civil construction plans to
verify compliance with the geotechnical report(s). The geotechnical engineer shall submit a
sealed letter stating that he/she has reviewed the civil construction plans and in their opinion
the plans and specifications meet the intent of the report(s).
DocuSign Envelope ID: 44E7B13B-E61D-42E2-9010-CB07930C65F3
City of Renton Department of Community & Economic Development
Mei Lin Short Plat
Staff Report to the Environmental Review Committee
LUA20-000060, SHPL-A, ECF, MOD
Report of August 10, 2020 Page 3 of 5
SR_ERC Report_Mei Lin SP_200806_v3_FINAL2
C. Exhibits
Exhibit 1: Environmental Review Committee (ERC) Report
Exhibit 2: Site Plan
Exhibit 3: Landscape Plan
Exhibit 4: Arborist Report
Exhibit 5: Tree Retention Plan
Exhibit 6: Drainage Report, prepared by Abbey Road Group, dated February 18, 2020
Exhibit 7: Conceptual Drainage Plan
Exhibit 8: Conceptual Utilities Plan
Exhibit 9: Grading Plan
Exhibit 10: Geotechnical Report, prepared by Bergquist Engineering Services, dated October 7, 2017
Exhibit 11: Review of Geotechnical Report, prepared by GeoSciences, dated May 11, 2020
Exhibit 12: Updated Geotechnical Report, prepared by Krazan & Associates, dated July 9, 2020
Exhibit 13: Second Review of Geotechnical Report, prepared by GeoSciences, dated July 16, 2020
Exhibit 14: Public Comment letters
D. Environmental Impacts
The proposal was circulated and reviewed by various City Departments and Divisions to determine whether the
applicant has adequately identified and addressed environmental impacts anticipated to occur in conjunction
with the proposed development. Staff reviewers have identified that the proposal is likely to have the following
probable impacts:
1. Earth
The subject site is located in an area with a sensitive slopes (15-40%), protected slopes (>40%), a high
landslide hazard, and a high erosion hazard. As such, the applicant submitted a Geotechnical Report,
prepared by Bergquist Engineering Services, dated October 17, 2017 (Exhibit 10). Due to the complexity
of the report and the extensive geotechnical hazards on the site, staff elected to utilize an outside
consultant to review the initial report for accuracy and comprehensiveness. Staff also received two
public comments from property owners directly to the south of the project site (Exhibit 14). Both letters
expressed concern with the potential risk for the construction on the project site to increase the risk of
slope failure that would ultimately impact their properties.
The consultant hired, Lyle Stone of GeoEngineers, reviewed the Bergquist geotechnical report and
provided the City and the applicant with six recommendations related to the errors or omissions in the
original analysis (Exhibit 11). The applicant submitted a new geotechnical report prepared by Krazan and
Associates on July 9, 2020 (Exhibit 12) that addressed each recommendation made by the City’s
secondary reviewer. GeoSciences reviewed the new report and determined that it adequately addressed
the shortcomings identified in the original report (Exhibit 13). Therefore the analysis by staff is limited to
the data and findings of the new report.
The ground surface starting from proposed Lot 3 slopes down at a shallow gradient from the north
property line to the crest of the declining steep slope. The sloped area is primarily covered with
blackberry branches on the shallower first section and second/third growth deciduous trees on the
steeper slope faces. The geotechnical consultant utilized the results of two test borings drilled to a
depth of 31 feet at the western edge of proposed lot three. Below approximately eight (8) inches of
organic topsoil, approximately 13.5 feet of very loose to medium-dense undocumented fill was
DocuSign Envelope ID: 44E7B13B-E61D-42E2-9010-CB07930C65F3
City of Renton Department of Community & Economic Development
Mei Lin Short Plat
Staff Report to the Environmental Review Committee
LUA20-000060, SHPL-A, ECF, MOD
Report of August 10, 2020 Page 4 of 5
SR_ERC Report_Mei Lin SP_200806_v3_FINAL2
discovered. Extending between 1.5 and 17 feet below the undocumented fill to a total depth of 31 feet
(limit of the boring), a layer of native glacial soils consisting of medium dense, silty sand with gravel was
found. Groundwater was not discovered within either boring. However, the report notes that due to
the borings occurring during the dry season, groundwater levels may be different in the winter months
due to seasonal fluctuations. The report did not identify any long term issues associated with ground
water on the site and only cautioned that fluctuating levels may pose a challenge during construction.
Krazan & Associates conducted a slope stability analysis using both static and seismic conditions due to
the presence of geotechnical hazards near the development. The stability of the uppermost soil units
were the primary target of the analysis. Software programs utilized by the consultant estimated a Factor
of Safety (FOS) coefficient for both the static condition and seismic condition in order determine risk of
slope failure. If a FOS is less than 1.00, the slope is considered unstable, while an FOS of greater than
1.00 indicates the slope is stable. The estimated FOS for a static condition was calculated to be
approximately 2.84 and the estimated FOS for a seismic event was calculated to be 1.34. Both FOS
exceed the calculated Factor of Safety developed to reflect specific site conditions (1.5 FOS for static and
1.1 FOF for seismic). Therefore, the risk of slope failure for both conditions is low. Based on the
minimum 30-foot distance between the proposed new home on Lot 3 and the toe of the slope (15-foot
buffer from steep slope and 15-foot structure setback from buffer), the report concludes that the
proposed development on Lot 3 would not adversely impact the existing western steep slopes or
increase the threat of the geological hazard to the adjacent or abutting properties to the south.
The report specifically recommends that no disturbance of the vegetated setback area occur during
development of the site. Short term activities such as the installation of new utilities for the home would
be considered allowable but should be minimized to as much extent as possible, and any disturbed
vegetation should be replaced as quickly as possible. No excavation, except for the required utilities,
may occur within the total 30 foot buffer area. In order to ensure that the clearing limits are respected
during the site preparation phase, staff recommends as a mitigation measure that the applicant retain a
licensed geotechnical engineer to be present during any earthwork related to site preparation on Lot 3.
The engineer shall be responsible for ensuring that the recommendations contained within the Krazen &
Associates report be followed. In addition, staff recommends as a mitigation measure that the applicant
be required to erect a 6-foot tall temporary chain-link fence with signage identifying the adjacent
geologic hazards at a distance of 30 feet from the toe of the slope (15-foot buffer and additional 15-foot
structure setback). The fencing would be installed prior the start of any on-site work and remain in place
until all structures on Lot 3 receive a Certificate of Occupancy. The fence shall be affixed to the ground
using metal stakes or similar to prevent movement. In addition, staff recommends as a mitigation
measure that the applicant’s geotechnical engineer review the project’s civil construction plans to verify
compliance with the geotechnical report(s). The geotechnical engineer should submit a sealed letter
stating that he/she has reviewed the civil construction plans and in their opinion the plans and
specifications meet the intent of the report(s).
The report concludes with recommendations for foundations, building setbacks, and site preparation for
proposed Lot 3. Based on the type of soils discovered and slope stability analyses performed,
conventional spread footings typically utilized for residential structures are appropriate for the site if
proper footing depths are utilized. The report recommends a minimum foot depth of 18 inches below
soil grade. Alternatively, the report identifies the potential to utilize a deep foundation system utilizing
drilled piers or driven piles would transmit the structure loads through any weak, upper soils to the
underlying, stronger soils encountered at a depth of approximately 20 feet below the ground surface.
The report recommends that a geotechnical engineer be present on the site to observe structural fill
placement and make real-time recommendations based on the conditions observed. Due to the specific
recommendations outlined in the geotechnical report related to the soil conditions on the site and high
probability of slope failure, staff recommends as a mitigation measure that the applicant comply with all
recommendations in the provided report or an updated report submitted with the building permit.
DocuSign Envelope ID: 44E7B13B-E61D-42E2-9010-CB07930C65F3
City of Renton Department of Community & Economic Development
Mei Lin Short Plat
Staff Report to the Environmental Review Committee
LUA20-000060, SHPL-A, ECF, MOD
Report of August 10, 2020 Page 5 of 5
SR_ERC Report_Mei Lin SP_200806_v3_FINAL2
The applicant has indicated the project would result in approximately 11,000 square feet of new
impervious area.
Mitigation Measures:
1. The applicant shall comply with the recommendations of the geotechnical report
prepared by Krazen & Associates, July 9, 2020, or an updated report submitted at a later
date.
2. The applicant shall retain a licensed geotechnical engineer to be present on site during
any earthwork activities related to site preparation on proposed Lot 3. The engineer
shall be responsible for ensuring that the recommendations in the Krazen & Associates
report, dated July 9, 2020 (or an updated report), are followed.
3. The applicant shall erect a 6-foot tall temporary chain-link fence at the edge of the 15-
foot buffer and additional 15-foot structure setback (total of 30 feet) in order to ensure
no disturbance of vegetation in the area. The fencing shall be affixed to the ground
using metal stakes or similar to prevent movement and shall include warning signage
regarding the risks of any disturbing vegetation or earth in the buffer. The fencing shall
be installed prior to the start of any work on the site and shall remain in place until all
structures on Lot 3 receive a sign-off on the building permit final inspection.
4. The applicant’s geotechnical engineer shall review the project’s civil construction plans
to verify compliance with the geotechnical report(s). The geotechnical engineer shall
submit a sealed letter stating that he/she has reviewed the civil construction plans and
in their opinion the plans and specifications meet the intent of the report(s).
Nexus: SEPA Environmental Review, RMC 4-4-060 Grading, Excavation and Mining Regulations
E. Comments of Reviewing Departments
The proposal has been circulated to City Department and Division Reviewers. Where applicable, their comments
have been incorporated into the text of this report and/or “Advisory Notes to Applicant.”
Copies of all Review Comments are contained in the Official File and may be attached to this report.
DocuSign Envelope ID: 44E7B13B-E61D-42E2-9010-CB07930C65F3